As far as they could inform, that sound may come maybe from the stress or vibrations of the unit rubbing up against the glass of the window. They may be wrong, but either way, the noise is brief, and it disappears rapidly. Don’t fall into the trap of buying a https://fullservicehvaccompanyinn69654.boyblogguide.com/4689151/some-of-window-ac-installation-burbank-city